The percentage of Kentuckians without health insurance fell to 6 percent in 2015 from 15 percent in 2010 under the Affordable Care Act, according to new data from the U.S. Department of Health and Human Services.

Only Nevada, Oregon and California posted larger percentage declines in uninsured. Kentucky now ranks below the national average of 9.4 percent.

The department reported that 404,000 Kentuckians gained coverage between 2010 and last year, a number nearly equal to the combined population of Lexington and neighboring Madison County.

And as one of the 31 states that expanded Medicaid under Obamacare, Kentucky’s enrollment for Medicaid and the Children’s Health Insurance Program doubled from 600,000 to 1.2 million. Of those, more than 555,000 were enrolled in CHIP.

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The numbers, however, do not measure the impact of Gov. Matt Bevin’s plan to dismantle Kentucky’s state health care exchange. On Nov. 1, the Bevin administration phased out the state’s health care enrollment platform, and enrollment now takes place through the federal health care exchange.

Bevin’s Medicaid plan may look a lot like neighboring Indiana’s, which was designed by Seema Verma under Gov. Mike Pence. Verma is President-elect Donald Trump’s choice to lead the Centers for Medicare and Medicaid Services.

Additionally, Trump and Republican leaders in Congress have pledged to repeal the law, creating uncertainty for the state’s newly covered residents.

For several years, the law’s opponents have vowed to repeal and replace it, though they’ve offered few details on the replacement.

Any replacement will likely preserve the law’s most popular components. The law required insurers to cover people with pre-existing health conditions and to allow children to remain on their parents’ health plans up to age 26.

About 31,000 Kentuckians under age 26 are insured under their parents’ health care plans, according to HHS.

And about 33 percent of Kentuckians under 65 have a pre-existing health condition that could have prevented them from getting coverage before the law was implemented, one of the highest percentages in the country, according to the Kaiser Family Foundation.